Photographic materials which contain barrier layers and antihalation layers

ABSTRACT

A lyophobic barrier layer consisting of a salt of an acetate of polyvinyl alcohol or of a hydroxyl-containing copolymer and an aldehyde sulfonic acid is arranged between the layer support and the antihalation layer of a photographic material, the layer support of which contains plasticisers.

United vStates Patent Kruck May 27, 1975 PHOTOGRAPHIC MATERIALS WHICH CONTAIN BARRIER LAYERS AND [56] References Cited ANTIHALATION LAYERS FOREIGN PATENTS OR APPLICATIONS [75] Inventor: Peter Kruck, Cologne, Germany 819,945 9/1959 United Kingdom 96/87 A [73] Assignee: Agia-Gevaert Aktiengesellschaft,

Primary ExamznerRonald H. Smith Leverkusen Bayerwerk Germany Attorney, Agent, or Firm-Connolly and Hutz [22] Filed: June 4, 1973 21 Appl. No.: 366,286 1 ABSTRACT A lyophobic barrier layer consisting of a salt of an acetate of polyvinyl alcohol or of a hydroXyl-containing [30] Forelgn Apphcanon Pnonty Dam copolymer and an aldehyde sulfonic acid is arranged June 8, 1972 Germany 2227889 between the layer Support and the antihalation layer A f ht h' t'l,thl tfh'h 52 US. Cl 96/84 R; 96/87 R; 96/87 A g j g g g gj ig em e ayer Supp w [51] Int. Cl G03c 1/84 5 10 Claims, N0 Drawings Field of Search 96/84 R, 87 A, 87 R PHOTOGRAPHIC MATERIALS WHICH CONTAIN BARRIER LAYERS AND ANTIHALATION LAYERS This invention relates to the production'of photographic film materials with improved alkalisoluble antihalation layers.

It is known to apply antihalation layers to the backs of films, in particular on miniature films and cine films. These antihalation layers generally consist of a lightabsorbing dye dispersed in a binder. The dye and binder are selected so that the layers will be decolourised or dissolved whilst the photographic material is processed. The light-absorbing dyes in the antihalation layers may be carbon black or certain organic dyes. The binders used are mainly film-forming high molecular weight organic polymers which contain carboxyl groups so that they can form water-soluble salts in an alkaline medium. Antihalation layers which contain carbon black as dye, for example, can therefore be removed with suitable alkaline baths before development while layers which contain organic dyes can be dissolved away in the alkaline developer bath. Antihalation layers with organic dyes are therefore used mainly in films which are required to be developed by a simple process without the use of additional baths and me chanical aids. Antihalation layers using organic dyes are usually applied from organic solvents, e.g. alcohols or esters.

The presence of a sufficiently large number of carboxyl groups in the binder is not the only factor which ensures that antihalation layers which contain organic dyes can easily be removed in alkaline developer baths. It has been found that if film supports which contain plasticiser are used (for example cellulose acetate supports), the solubility of the antihalation layers decreases considerably if the film material is treated in developer baths which have been prepared using hard water. The reason for this reduction in solubility is partly the insufficient complex formation of the calcium and magnesium salts in the tap water, especially if developer concentrates are used, and partly the migration of plasticisers from the film support into the antihalation layer.

It is an object of this invention to provide photographic materials with antihalation layers which will be completely soluble in alkaline baths prepared with hard water without the need for the addition of complexforming agents or water softeners.

A process for the production of photographic materials containing alkali-soluble antihalation layers on layer supports which contain plasticiser has now been found which is characterised in that a lyophobic barrier layer consisting of a salt of an acetal of polyvinyl alcohol or of a hydroxyl-containing copolymer and an aldehyde sulfonic acid is arranged between the layer support and the antihalation layer.

The aldehyde sulfonic acids used for forming the acetals may be either aliphatic or aromatic. Butyraldehyde sulfonic acid, acetaldehyde sulfonic acid, propionaldehyde sulfonic acid and methyl ethyl acetaldehyde sulfonic acid are examples of aliphatic aldehyde sulfonic acids.

The following are examples of suitable aromatic aldehyde sulfonic acidszbenzaldehyde sulfonic acid-(2), benzaldehyde sulfonic acid(4), benzaldehyde disulfonic acid-(2,4) and substituted aldehyde sulfonic acids such as 4-chloro-benzaldehyde sulfonic acid-(2), 5-

nitrobenzaldehyde sulfonic acid-(2), 2,6- dichlorobenzaldehyde sulfonic acid-(3) and 3-methyl benzaldehyde sulfonic acid-(2).

Suitable polyvinyl alcohols are characterised by having a K-value (relative measure of the degree of polymerisation) of between 30 and 90 and a vinyl acetate content of 0-50 percent. Copolymers which contain other vinyl alcohol groups are also suitable, for example those containing vinyl chloride, vinylidene chloride, vinyl methyl ether acrylonitrile, styrene, etc.

The aldehyde sulfonic acids used for acetalisation of the polyvinyl alcohol may be partly replaced by unsubstituted aldehydes which do not contain sulfonic groups but it is important to ensure that the resulting products do not undergo swelling in the organic solvents used for preparing the antihalation layer.

The preparation of acetals of polyvinyl alcohol or of hydroxyl-containing copolymers with aldehyde sulfonic acids is already known and has been described, for example, by O. Horn in Monomeric and polymeric vinyl acetate and its derivatives, Chemistry and Industry, 1955, page 1748. Preparation of these acetals is carried out in aqueous or methanolic solution, if desired with the addition of other organic solvents as well as the ad dition of mineral acids as acetalisation catalysts, preferably at temperatures of between 50C and C.

The solvent used for preparing the acetal-containing barrier layers according to this invention is preferably water or a mixture of water with, for example, methanol, ethanol, propanol, acetone or methyl ethyl ketone. If necessary, other organic solvents which are immiscible with water may be used in addition, e.g. ethyl acetate, butyl acetate, methylene chloride, chloroform or l,2dichloroethane.

An excellent bond is obtained between the antihalation layers which contain alkali-soluble polymeric binders and the acetal-containing barrier layers according to the invention. On the other hand, the barrier layers do not adhere firmly to the cellulose acetate layers nor mally used as film supports and consequently the antihalation layer and barrier layer of the photographic material together are liable to be transferred to the emulsion layer when subjected to moisture and heat when the antihalation layer comes into contact with the emulsion layer when the film is rolled up. This difficulty, however, can easily be overcome by first coating the cellulose acetate support with a suitable subbing layer instead of applying the barrier layer directly to the support. The usual subbing layers used for emulsion layers are suitable for this purpose but much smaller quantities than usual are required, about one tenth of the quantity normally applied to an emulsion layer being sufficient for use as a subbing layer for a barrier layer according to the invention. The subbing layers commonly used generally contain gelatine and organic acids such as acetic acid, salicilic acid or phthalic acid and are applied to the film support from mixtures of water, methanol, ethanol, acetone, methyl ethyl ketone, methylene chloride and chloroform. The substrate layers may contain hardeners, dyes and polymers such as cellulose acetate (Ullmanns Enzyklopadie der technischen Chemie 3rd edition 1962, volume 13, page 633).

Another and preferred method of achieving a firmer bond between the barrier layer and cellulose acetate supports consists of directly anchoring the barrier layer into the surface of the film by means of solvents which have a swelling action. Suitable swelling agents for film supports of cellulose acetate are. for example, acetone, methyl ethyl ketone, methylene chloride, chloroform, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether monoacetate, dioxane and dimethylformamide. Choice of a suitable swelling agent depends on the solubility properties of the acctals. In most cases a certain minimum proportion of water is necessary to obtain stable solutions. The degree of swelling of the form support should not exceed a certain maximum because otherwise plasticiser is extracted from the film support and accumulates in the barrier layer from which it can migrate to the antihalation layer. Satisfactory results are obtained with mixtures of water, methanol and acetone in which the acetone content should not exceed 5060 vol.percent. According to a preferred method, the barrier layer is applied from aqueous solutions which contain -60 vol.-percent of acetone,

Application and drying of the barrier layers according to the invention may be carried out by the usual methods employed for the production of photographic film supports, for example the barrier layer may be applied with sprays, brushes, rollers, coating knives or air brushes or by any other spread coating techniques. The optimum quantity applied depends on the method employed for improving the bond between the barrier layer and the support. If the barrier layers are applied to the subbing layers from aqueous or aqueousalcoholic solutions, it is sufficient to apply 0.02 0.10 g/m the quantity applied in this case being preferably 0.04 0.08 g/m Larger quantities are necessary if the barrier layer is directly anchored to the film support by means of swelling solvents, i.e. 0.04 020 g/m and preferably 0.07 0.12 g/m The barrier layer according to the invention is finally coated with an antihalation layer which consists of a binder in which an organic antihalation dye is dispersed. Suitable binders for these antihalation layers are copolymers of maleic acid, acrylic acid methacrylic acid, itaconic acid or crotonic acid with styrene, vinyl acetate, vinyl ethers, acrylonitrile, acrylic acid esters or vinyl chloride, especially copolymers of nitrostyrenemaleic acid as described in Belgian Pat. No. 552,915 or copolymers of acrylonitrile/vinyl ether/maleic acid semiester according to German Pat. No. 1,028,881 or condensation products of p-hydroxybenzoic acid and formaldehyde as described in German Pat. No. 1,240,397. The organic dyes used in the antihalation layers may belong to almost any known class of dyes, in particular triphenylmethane, oxanole, merocyanme, arylidene, pyrrolocyanine and styryl dyes. The dyes described in German Pat. No. 1,008,114 have proved to be particularly suitable. Suitable organic solvents for application of these antihalation layers are, for example, alcohols such as methanol, ethanol, propanol and butanol or esters such as ethyl acetate and butyl ace- The following are plasticisers which have a deleterious effect on the solubility of antihalation layers for the this invention: triphenyl phosphate, tricresyl phosphate, trichloroethyl phosphate, dibutyl phthalate, dimethyl phthalate, benzyl butyl phthalate, dimethyl glycol phthalate, dicyclohexyl phthalate, glycerol triacetate and dibutyl adiphate.

Complete solubility of the coating on the back of the film support may advantageously be tested with develpurpose of oper solutions prepared from concentrates which con tain only relatively small amounts of complex-forming agents for those consitituents of water which cause the so-called hardness of water. For the purpose of the text, the developer concentrate should be diluted with water which has about 15 of German hardness (DH). One degree DH corresponds to 10 mg of calcium oxide in 1 litre of water. If necessary, the water may be adjusted to the minimum hardness with calcium chloride in accordannce with DIN 53910 (German Industrial Standards).

Antihalation layers bonded to barrier layers in accordance with the invention have all the properties required for this purpose to an outstanding degree. Their preparation does not afford any special difficulties. They dissolve completely in aqueous alkaline developer baths which contain normal water, that is to say water which has not been softened, without the aid of water softeners. They are photographically inert and therefore have no deleterious effect on the light sensi tivity of the layers. In addition, the barrier layers according to the invention have a surprisingly advantageous effect on the electrostatic properties of the film material in that they substantially prevent accidental exposure of the film. This antistatic action can be determined by measuring the electric surface resistance at 20C and 60 percent relative humidity according to DIN 53482.

EXAMPLE 1 The following subbing solution is applied to a film support consisting of parts by weight of cellulose acetate with an acetic acid content of 61.2 percent and 15 parts by weight of triphenyl phosphate:

1 g of gelatine, 2 ml of water, 192 ml of methanol, 780 ml of acetone,

0.33 g of phthalic acid and 0.92 g of a cellulose acetate diester, e.g.

the product marketed by Farbenfabriken Bayer under the trade designation Cellit F 700.

A barrier layer of the following composition is applied to the substrate layer after drying:

2.0 g of the sodium salt of an acetal of polyvinyl alcohol with butyraldehyde sulfonic acid,

500 ml of water and 500 ml of methanol.

Lastly, an antihalation layer of the following composition is applied:

A developer of the following composition is used for testing for the presence of any residue:

50 g of p-aminophenol,

made up to l000 ml with water.

1 part by volume of the developer is diluted with 50 parts by volume of water of l DH. The film is developed for minutes at C. For comparison, a film material with a similar substrate coating on the back 10 but without barrier layer and another film material without barrier layer and without substrate layer are tested.

Layers on back of Surface Residue on back of film film resistance after development Example I 8 IOOhm none ditto but without barrier layer 2 l0 Ohm very heavy ditto but without barrier layer or substrate layer 2 l0 Ohm very heavy EXAMPLE 2 A solution of the following composition is applied as barrier layer to a film support with substrate according to example 1:

3.0 g of the sodium salt of an acetal of polyvinyl alcohol with benzaldehydedisulfonic acid-(2,4),

of water and of methanol.

ml ml EXAMPLE 3 A solution of the following composition is applied directly to a film support according to example I as barrier layer:

5.0 g of the sodium salt of an acetal of polyvinyl alcohol and butyraldehyde sulfonic acid, 150 ml of water, 350 ml of methanol and 500 ml of acetone After application of an antihalation layer according to example 1, the surface resistance on the back of the film is 1.5. 10 Ohm. The layer at the back is completely soluble in the developer.

EXAMPLE 4 i The following barrier layer is applied directly to a film support described in example 1:

6.5 g of the sodium salt of an acetal of polyvinyl alcohol and benzaldehyde- 5 sulfonic acid-(4).

200 ml of water, 300 ml of methanol and 500 ml of acetone.

An antihalation layer subsequently applied as described in example l is completely soluble in the developer. The surface resistance is 5. 10 Ohm.

What we claim is:

l. A photographic material comprising a support having a pair of converse major surfaces and containing at least one plasticizer, the obverse of said converse surfaces carrying a light-sensitive emulsion layer, the reverse of said converse surfaces carrying a barrier layer comprising a polymer which contains at least one salt of an acetal of vinylalcohol and an aldehyde sulphonic acid, on said barrier layer an antihalation layer, a binder in said antihalation layer for providing a solubility corresponding to complete solubility in a developer of the following composition:

paminophenol potassium sulfite potassium hydroxide potassium bromide ethylene diaminotetraacetic acid Water up to 1000 ml 50 g 500 g 50 g 20 g 4. A material as claimed in claim 3 in which 0.04 to 0.08 g/m has been applied.

5. A material as claimed in claim 1 in which the casting solution for the barrier layer contains at least one solvent capable of swelling the support.

6. A material as claimed in claim 5 in which 0.04 to 0.20 g/m of barrier layer has been applied.

7. A material as claimed in claim 6 in which 0.07 to 012 g/m has been applied.

8. A material as claimed in claims 5 in which the casting solution contains water and acetone.

9. A material as claimed in claim 8 in which the casting solution contains 20 to 60 vol percent acetone.

10. A material as claimed in claim 1 in which the support is cellulose acetate. 

1. A PHOTOGRAPHIC MATERIAL COMPRISING A SUPPORT HAVING A PAIR OF CONVERSE MAJOR SURFACES AND CONTAINING AT LEAST ONE PLASTICIZER, THE OBSERSE OF SAID CONVERSE SURFACES CARRYING A LIGHT-SENSITIVE EMULSION LAYER, THE REVERSE OF SAID CONVERSE SURFACES CARRING A BARRIER LAYER COMPRISING A POLYMER WHICH CONTAINS AT LEAST ONE SALT OF AN ACETAL OF VINYLALCOHOL AND AN ALDEHYDE SUFPHONIC ACID, ON SAID BARRIER LAYER AN ANTIHALATION LAYER, A BINDER IN SAID ANTIHALATION LAYER FOR PROVIDING A SOLUBILITY CORRESPONDING TO COMPLETE STUBILITY IN A DEVELOPER OF THE FOLLOWING COMPOSITION:
 2. A material as claimed in claim 1 in which there is present a subbing layer between the barrier layer and the support.
 3. A material as claimed in claim 2 in which 0.02 to 0.10 g/m2 of an aqueous or aqueous-alcoholic subbing solution has been applied.
 4. A material as claimed in claim 3 in which 0.04 to 0.08 g/m2 has been applied.
 5. A material as claimed in claim 1 in which the casting solution for the barrier layer contains at least one solvent capable of swelling the support.
 6. A material as claimed in claim 5 in which 0.04 to 0.20 g/m2 of barrier layer has been applied.
 7. A material as claimed in claim 6 in which 0.07 to 0.12 g/m2 has been applied.
 8. A material as claimed in claims 5 in which the casting solution contains water and acetone.
 9. A material as claimed in claim 8 in which the casting solution contains 20 to 60 vol percent acetone.
 10. A material as claimed in claim 1 in which the support is cellulose acetate. 